I did a search on this and most of the answers I got were on the HVAC slider/vacuum problems.

The vents in my car blow a very, very small amount of air when any setting is used. The defroster barely works past a few inches of the vent. The driver side vent blows only a very small amount of air, and only the top vent of the two in the middle work. The passenger side vent does not work at all.

What controls the flow of air to the vents? Is there some sort of tubing that may have fallen off the back of the vents or something? I really have no idea where to begin looking for problems.

I really need to fix this though, since winter is approaching and I can barely see out of my windshield when it frosts up.

 

I don't think there is anything that can fall off to the point that NO setting has air blowing out. It can REDIRECT the air to different vents (defrost being the default position if the HVAC controls are not being fed any vacuum from the engine to move them, if there is a problem with that system for some reason) but it can't just block everything off, to my knowlege. If the fan is running at the correct speed the air has to be going somewhere. Either that or a squirrel built a nest in your heater box!

Do the selector controls allow what little air you are getting to be redirected to the proper vents selected?

Does the fan speed control clearly work and run the fan at different speeds from low to hurricane?

Start from there and I'll be there are guys a lot better than me at HVAC stuff on this board who could probably help you figure it out.

 

Like you said, the air HAS to be going somewhere because I can definately hear the change in flow of air between each of the four settings (especially the "High" speed, which sounds like a small vacuum cleaner is on in my car). The problem is, I just don't know where it is going.

I'm going to assume that the temperature control slider works because as I move the slider to the right, the temperature of the air gets progressively warmer. I only say assume because I really have no idea if the A/C works or not. It doesn't blow out hot air, but it'd definately not cold either. It works pretty much as well as the vent does as far as cold air is concerned.

The selector controls do work, but I am about to go check to make 100% sure they work properly. I'll be back in about 10 minutes to report my findings.

Thanks for your help, Damon. I'll be back in a minute.

 

After checking it out, the selector controls work in the same way for every single thing except for the defroster. With the defroster on, it blows a slight amount of air out of the defroster vent and a lot of air out of the top middle vent. It also seems to be blowing air out of the bottom of the radio pod on the passenger side floor.

All the other settings are the exact same: driver's side has a small amount of air, the top middle blows quite a bit, the bottom middle blows no air at all, and neither does the passenger side.

EDIT: Forgot to mention, no matter what setting it is on, there seems to be a lot of air blowing through the back of the radio pod on the passenger side, but not on the driver side.

 

Because you're getting air at the top middle vents, I'd suggest the system has gone to the default position and there's a vac problem, which is common with these cars.

JamesC

 

I thought about that, too. But other people with that problem report only having air coming out of the defroster vent and nothing else.

Just in case it is, though, I might as well check it out anyway. Where would any vacuum lines for the AC/heater vents be located? I assume they would be in a different place in an LG4 than they would be in a TPI or TBI car.

 

In many cases, the problem lies in the actuator switch at the rear of the HAVC control head. This switch, through movement of the slider, routes air to the various 'air' positions: defrost, vent, etc. If it's leaking (and you might be able to hear the leak if you clamp you ear to the control head), then a simple replacement is the answer.

JamesC

 

Thanks, JamesC. I'll check that out as soon as I can.

 

that vacuum actuator switch is commonly leaking at the vacuum lines. do you hear a leak at all? all the vacuum lines come together in a single manifold type thing that attaches to that switch. although it may appear to be ok, and sometimes work ok, it's not always 100%. if that's not your problem, chasing vacuum lines going in to the dash to open various "doors" is not fun.

with that said, if you remove that connector off the actuator switch, swab the inside of each of those vacuum lines with vaseline (using a q-tip), and that might fix the problem. if you still have a leak there, you may have to take more drastic measures like i did, but i won't get in to that right now... anyhow, a couple of recommendations: (1)take your stereo out to work in there. you'll probably be glad you did. (2)when you go to pop off those fasteners from the back of that switch, cover your tunnel area under your stereo with a rag cuz if those things take flight, it'll be much easier to contain them and find them.

KAM

 

Ok, guys. Either my car is the exception to the rule (unlikely), or I'm an idiot because the only thing that looks like a vacuum line behind my controls is the thing that changes the hot/cold setting. It looks like it has some kind of plunger that goes into one vacuum line. Is this what you guys are referring to?

Otherwise, I just see a dusty mess of wires that have not been tinkered with in 20 years.

 

Pull the HVAC control head out a bit. Look on the right side. The actuator switch is circular. Several 'fingers' protrude from it and the vac harness, composed of several different colored lines, slips over those 'fingers'.

JamesC